Study of pallial neurogenesis in shark embryos and the evolutionary origin of the subventricular zone

The dorsal part of the developing telencephalon is one of the brain areas that has suffered most drastic changes throughout vertebrate evolution. Its evolutionary increase in complexity was thought to be partly achieved by the appearance of a new neurogenic niche in the embryonic subventricular zone (SVZ). Here, a new kind of amplifying progenitors (basal progenitors) expressing Tbr2, undergo a second round of divisions, which is believed to have contributed to the expansion of the neocortex. Accordingly, the existence of a pallial SVZ has been classically considered exclusive of mammals. However, the lack of studies in ancient vertebrates precludes any clear conclusion about the evolutionary origin of the SVZ and the neurogenic mechanisms that rule pallial development. In this work, we explore pallial neurogenesis in a basal vertebrate, the shark Scyliorhinus canicula, through the study of the expression patterns of several neurogenic markers. We found that apical progenitors and radial migration are present in sharks, and therefore, their presence must be highly conserved throughout evolution. Surprisingly, we detected a subventricular band of ScTbr2-expressing cells, some of which also expressed mitotic markers, indicating that the existence of basal progenitors should be considered an ancestral condition rather than a novelty of mammals or amniotes. Finally, we report that the transcriptional program for the specification of glutamatergic pallial cells (Pax6, Tbr2, NeuroD, Tbr1) is also present in sharks. However, the segregation of these markers into different cell types is not clear yet, which may be linked to the lack of layering in anamniotesThis work was supported by the Spanish Ministerio de Economía y Competitividad-FEDER (BFU2014-5863-1P)S

Influence of very low doses of mediators on fungal laccase activity - nonlinearity beyond imagination

Laccase, an enzyme responsible for aerobic transformations of natural phenolics, in industrial applications requires the presence of low-molecular substances known as mediators, which accelerate oxidation processes. However, the use of mediators is limited by their toxicity and the high costs of exploitation. The activation of extracellular laccase in growing fungal culture with highly diluted mediators, ABTS and HBT is described. Two high laccase-producing fungal strains, Trametes versicolor and Cerrena unicolor, were used in this study as a source of enzyme. Selected dilutions of the mediators significantly increased the activity of extracellular laccase during 14 days of cultivation what was distinctly visible in PAGE technique and in colorimetric tests. The same mediator dilutions increased demethylation properties of laccase, which was demonstrated during incubation of enzyme with veratric acid. It was established that the activation effect was assigned to specific dilutions of mediators. Our dose-response dilution process smoothly passes into the range of action of homeopathic dilutions and is of interest for homeopaths

The nitric oxide synthase (NOS)-like immunoreactive extrahypophysial projections of the neurosecretory preoptic nucleus of the electric ray (elasmobranchs) suggest a neuroregulatory role for this nucleus.

The extrahypohysial projections of the neurosecretory preoptic nucleus (PON) of the electric ray were studied with the aid of an antibody against nitric oxide synthase (NOS). PON neurons were the only NOS-like-immunoreactive (NOS-ir) cells in the brain. These neurons gave rise to both hypophysial and extrahypophysial NOS-ir projections. Some fibres coursed from the PON to the neurointermediate lobe in the preoptic-hypophysial tract. Other NOS-ir fibres coursed either rostrally or caudally forming terminal fields in the telencephalon (subpallial region), diencephalon (preoptic nucleus, ventrolateral thalamus and posterior recess nucleus), tuberal region (area tegmentalis ventralis and substantia nigra), mesencephalon (lateral tegmentum), rhombencephalon (isthmal nucleus, vagal viscerosensory column and ventrolateral reticular area) and the spinal cord (intermediate horn). The possible involvement of the extrahypophysial PON projections in neuroregulation of visceral centres is discussed

The electric lobes of the electric ray (Torpedo marmorata) are innervated by GABAergic fibres: immunocytochemical evidence for dual innervation of electromotoneurons.

It is currently thought that the electric lobes of electric rays are innervated by a single neuronal system, the oval nucleus system. In the work reported here, the innervation of the electric lobes was studied with silver staining methods, acetylcholinesterase histochemistry and gamma-aminobutyric acid (GABA) immunocytochemistry. Two types of axon were observed in the lobes: thick GABA-immunonegative fibres, which originated from the oval nucleus, and thin GABAergic fibres of unknown origin, here reported for the first time. Electromotoneurons were strongly acetylcholinesterase-positive. Non-GABAergic and non-cholinergic neurons were observed in the oval nucleus, which is innervated by GABA-immunoreactive fibres. These results suggest that GABA may modulate electric discharge both directly, by GABAergic fibres that project to the lobes, and indirectly, by GABAergic fibres that project to the oval nucleus

The neuronal system of the saccus vasculosus of trout (Salmo trutta fario and Oncorhynchus mykiss): an immunocytochemical and nerve tracing study.

The neuronal system of the saccus vasculosus of two species of trout was studied with immunocytochemical methods and carboindocyanine-dye (DiI) tract-tracing. The cerebrospinal-fluid-contacting neurons of the saccus were immunoreactive for gamma-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD), and neuropeptide Y (NPY). Immunostaining of alternate sections of the saccus vasculosus of fry with anti-GAD and anti-NPY indicated that these substances were colocalized. The tractus sacci vasculosi and the neuropil of the nucleus sacci vasculosi were also immunoreactive to these substances. The GABA, GAD, and neuropeptide Y immunoreactivity of the saccus vasculosus system appeared early in trout ontogeny. After applying DiI to various levels of the tractus sacci vasculosi of adult trout, we observed massive bilateral saccular projections to the nucleus sacci vasculosi and could follow the course of the sacco-thalamic tract. This tract extended in the subependymal region of the thalamus rostral to the nucleus sacci vasculosi and split into two small tracts that reached the subhabenular-preoptic region. Sacco-thalamic fibers formed extensive periependymal plexuses along their trajectory. Interestingly, no clear evidence of the existence of a saccopetal system was obtained. On the basis of these results, we postulate that the saccus vasculosus system modulates the function of centers of the posterior tubercle and periventricular thalamus

Distribution of choline acetyltransferase (ChAT) immunoreactivity in the brain of the adult trout and tract-tracing observations on the connections of the nuclei of the isthmus.

The distribution of cholinergic neurons and fibers was studied in the brain and rostral spinal cord of the brown trout and rainbow trout by using an antiserum against the enzyme choline acetyltransferase (ChAT). Cholinergic neurons were observed in the ventral telencephalon, preoptic region, habenula, thalamus, hypothalamus, magnocellular superficial pretectal nucleus, optic tectum, isthmus, cranial nerve motor nuclei, and spinal cord. In addition, new cholinergic groups were detected in the vascular organ of the lamina terminalis, the parvocellular and magnocellular parts of the preoptic nucleus, the anterior tuberal nucleus, and a mesencephalic tegmental nucleus. The presence of ChAT in the magnocellular neurosecretory system of trout suggests that acetylcholine is involved in control of hormone release by neurosecretory terminals. In order to characterize the several cholinergic nuclei observed in the isthmus of trout, their projections were studied by application of 1,1;-dioctadecyl-3,3,3;, 3;-tetramethylindocarbocyanine perchlorate (DiI) to selected structures of the brain. The secondary gustatory nucleus projected mainly to the lateral hypothalamic lobes, whereas the nucleus isthmi projected to the optic tectum and parvocellular superficial pretectal nucleus, as previously described in other teleost groups. In addition, other isthmic cholinergic nuclei of trout may be homologs of the mesopontine system of mammals. We conclude that the cholinergic systems of teleosts show many primitive features that have been preserved during evolution, together with characteristics exclusive to the group

Biosurfactants in cosmetic formulations: trends and challenges

Cosmetic products play an essential role in everyones life. People everyday use a large variety of cosmetic products such as soap, shampoo, toothpaste, deodorant, skin care, perfume, make-up, among others. The cosmetic industry encompasses several environmental, social and economic impacts that are being addressed through the search for more efficient manufacturing techniques, the reduction of waste and emissions and the promotion of personal hygiene, contributing to an improvement of public health and at the same time providing employment opportunities. The current trend among consumers is the pursuit for natural ingredients in cosmetic products, as many of these products exhibit equal, better or additional benefits in comparison with the chemical-based products. In this sense, biosurfactants are natural compounds with great potential in the formulation of cosmetic products given by their biodegradability and impact in health. Indeed, many of these biosurfactants could exhibit a prebiotic character. This review covers the current state-of-the-art of biosurfactant research for cosmetic purposes and further discusses the future challenges for cosmetic applications.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01–0145-FEDER-006684) and the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), as well as X. Vecino post-doctoral grant (SFRH/BPD/101476/2014). Also, the authors acknowledge the financial support from Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904).info:eu-repo/semantics/publishedVersio